There are four light-weight-rod samples A,B,C,D separately suspended by threads. A bar magnet is slowly brought near each sample and the following observations are noted

(i)A is feebly repelled
(ii)B is feebly attracted
(iii)C is strongly attracted
(iv)D remains unaffected

Which one of the following is true ?

B is of a paramagnetic material
C is of a diamagnetic material
D is of a ferromagnetic material
A is of a non-magnetic material

Solution

A → diamagnetic B →paramagnetic

C →Ferromagnetic D →Non-magnetic

The magnetic moment of a diamagnetic atom is

equal to zero
much greater than one
unity
between zero and one

Solution

The magnetic moment of a diamagnetic atom is equal to zero.

According to Curie’s law, the magnetic susceptibility of a substance at an absolute temperature T is proportional to

T²
¹⁄_T²
T
¹⁄_T²

Solution

According to Curie’s law,X_m α ¹⁄_T

A diamagnetic material in a magnetic field moves

perpendicular to the field
from stronger to the weaker parts of the field
from weaker to the stronger parts of the field
None of these

Solution

A diamagnetic material in a magnetic field moves, from stronger to the weaker parts of the field.

Current i is flowing in a coil of area A and number of turns N, then magnetic moment of the coil M is

NiA
^Ni⁄_A
^Ni⁄_√A
N²Ai

Solution

Magnetic moment linked with one turn = iA

Magnetic moment linked with N turn

= iNA amp-m².

Here A = Area of current loop.

A bar magnet, of magnetic moment \(\underset{M}{\rightarrow}\), is placed in a magnetic field of induction \(\underset{B}{\rightarrow}\). The torque exerted on it is

\(\underset{M}{\rightarrow}.\underset{B}{\rightarrow}\)
\(-\underset{M}{\rightarrow}.\underset{B}{\rightarrow}\)
\(\underset{M}{\rightarrow}\times \underset{B}{\rightarrow}\)
\(\underset{B}{\rightarrow}\times \underset{M}{\rightarrow}\)

Solution

We know that when a bar magnet is placed in the magnetic field at an angle q, then torque acting on the bar magnet

(τ) =MB sin M θ = \(\underset{M}{\rightarrow}\times \underset{B}{\rightarrow}\)

Note : This torque τ has a tendency to make the axis of the magnet parallel to the direction of the magnetic field.

If a diamagnetic substance is brought near north or south pole of a bar magnet, it is

attracted by the poles
repelled by the poles
repelled by north pole and attracted by the south pole
attracted by the north pole and repelled by the south pole

Solution

Diamagnetic substances do not have any unpaired electron. and they magnetised in direction opposite to that of magnetic field.Hence when they are brought to North or South pole of Bar magnet, they are repelled by poles.

For protecting a sensitive equipment from the external electric arc, it should be

wrapped with insulation around it when passing current through it
placed inside an iron can
surrounded with fine copper sheet
placed inside an aluminium can

Solution

The iron can produces a magnetic screening for the equipment as lines of magnetic force can not enter iron enclosure.

The magnetic materials having negative magnetic susceptibility are

non-magnetic
para magnetic
dia magnetic
ferro magnetic

Solution

X_m is negative for diamagnetic materials.

UnAttempted

0

Attempted

0

Correct

0

Wrong

0

Complete